JPH0745980Y2 - Circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a circuit board for a hybrid integrated circuit with improved packaging density.

[Prior Art] In recent years, component electrode lands such as chip components and through-hole electrode lands have come to be provided closer to each other for high-density mounting of a hybrid integrated circuit board. In this way, when mounting a chip component etc. near the through hole connection part, the molten solder reaches the through hole entrance part,
Sometimes it goes into the through-hole, and when the electrode conductor in the through-hole part is Ag or Ag-Pd, for example, defects such as poor conduction due to the so-called "Ag erosion" phenomenon that the Ag component diffuses and dissolves in the solder Could occur.

Therefore, in the conventional circuit board, a certain distance is provided between the component electrode land and the through-hole electrode land, and the through-hole electrode land is completely covered with the glass insulating layer.

That is, the structure of the conventional hybrid integrated circuit board having the through-hole connection portion is as shown in FIG. 4 (FIG. 4A is a top view and FIG. 4B is a sectional view). The component electrode lands 4 and 4'provided above have conductors exposed, but the electrode lands at the through holes 2 provided at a certain distance from them (through hole electrode lands). 3 is completely covered by the glass insulating layer 5. This is because when the solder paste 6 is printed on the component electrode lands 4 and 4 ', respectively, and the chip component 7 is mounted on the component electrode land, the molten solder flows into the through hole 2 when the chip component is connected and fixed by reflow heat treatment. This is to prevent contact with the through-hole electrode land.

[Problems to be solved by the invention] Higher component mounting densities in recent printed wiring boards have been more and more strongly demanded together with the miniaturization of components. When components are mounted near the holes, there is a possibility of Ag erosion and solder shorts between component lands, so the conventional circuit board structure with through-hole connections cannot achieve high density. there were.

The present invention provides a circuit board that can improve the mounting density by eliminating the factors that hinder the high density of the mounted components as described above.

[Means and Actions for Solving the Problem] Therefore, the present invention provides at least one through hole having a conductor layer formed on the inner wall surface, a through hole electrode land having an exposed conductor having the through hole at the center, and A circuit board for a hybrid integrated circuit having a component electrode land adjacent to it, wherein the inner wall of the hole of the through hole is an insulating glass layer so that a hollow cylinder of insulating glass inscribed therein is formed. The glass hollow cylinder is covered with a thin insulating glass whose both end portions are open like a trumpet, and the openings of the through holes are the inner circumference circles on both surfaces of the substrate, and the larger concentric circles are the outer circumference circles. Forming an annular body of layers, the annular body passing through the central portion of the through-hole electrode land and being passed through by a strip-shaped insulating glass layer coated on the through-hole electrode land. The chip is connected to the insulating layer around the hole electrode land, and the portion of the through hole electrode land which is not covered with glass cooperates with the adjacent partial electrode land to directly above the through hole or at a position close to the through hole. A circuit board having a structure that can be used as a component electrode land for mounting a component.

In the hybrid integrated circuit board of the present invention, there is a through hole in the center of the through hole electrode land, and the end of the through hole on the surface of the board is surrounded by a concentric circle having a diameter 10 to 20% larger than the diameter of the through hole. And is covered with a donut-shaped glass insulating layer pattern having an inner circumference of the through-hole opening circle, and the through-hole electrode land connects the donut ring with the glass insulating layer around the through-hole electrode land. Although it is divided into left and right by the insulating layer, the through-hole electrode land that is exposed without being covered by the insulating layer is mounted on the chip component directly above the through-hole or very close to the through-hole. Since it can be used as a component electrode land for electrical components, it may cause Ag erosion of the through-hole electrode or short circuit between component electrode lands. Without a high density hybrid integrated circuits than can be obtained. The present invention will be further described with reference to the following examples.

[Embodiment] FIGS. 1 to 3 illustrate a hybrid integrated circuit structure according to the present invention. FIG. 1A is a top view of a circuit board, and FIG.
Is a sectional view thereof. The structure will be described with reference to these drawings.

First, on the insulating substrate 1, a through-hole electrode land 3 which is an exposed conductor region having a through-hole 2 in the center and a component electrode land 4 which is different from the through-hole electrode land 3 are formed by screen printing. Next, a glass insulating layer (borosilicate glass) 5 is screen-printed on the inner wall surface of the through hole 2 and its extended portion as shown in the figure (see FIG. 1 above).

Next, the cream solder 6 is screen-printed on a part (the left half in the figure) of the region of the component electrode land 4 and the through-hole electrode land 3 which is not covered by the insulating layer 5 '(see FIG. 2).

Next, after the chip component 7 is placed, it is soldered by reflow heat treatment (see FIG. 3).

By the method described above, a high-density hybrid integrated circuit having chip components mounted directly above the through hole can be formed.

[Effects of the Invention] As described above, by using the hybrid integrated circuit substrate of the present invention, the packaging density is high, the Ag of the through-hole electrode conductor may be eaten, and the short circuit between the component electrode lands may occur. Low hybrid integrated circuits can be made.

[Brief description of drawings]

1 to 3 are explanatory views of a hybrid integrated circuit structure of the present invention. FIG. 1A is a top view of a circuit board and FIG. 3B is a sectional view thereof. FIG. 4 shows a conventional hybrid integrated circuit structure. FIG. 4 (a) is a top view and FIG. 4 (b) is a sectional view thereof. Explanation of symbols 1 ... Insulating substrate 2 ... Through hole 3 ... Through hole Electrode land 4, 4 '... Component electrode land 5, 5' ... Glass insulating layer 6 ... Cream solder 7 ... Chip component

Claims (1)

[Scope of utility model registration request] 1. At least one conductor layer is formed on an inner wall surface.
A circuit board for a hybrid integrated circuit having one through hole, a through hole electrode land made of an exposed conductor having the through hole in a central portion, and a component electrode land adjacent to the through hole, wherein a through hole conductor is formed. The inner wall of the hole is covered with an insulating glass layer so that a hollow cylinder of insulating glass inscribed therein is formed. An annular body of a thin insulating glass layer is formed on both surfaces of which the opening of the through hole is an inner circle and a larger concentric circle is an outer circle, and the annular body forms a central portion of the through hole electrode land. It is connected to the insulating layer around the through-hole electrode land by a strip-shaped insulating glass layer applied across the through-hole electrode land, The portion not covered with lath has a structure that can be used as a component electrode land for mounting a chip component directly above the through hole or close to the through hole in cooperation with the adjacent component electrode land. Characteristic circuit board.